1. Field of the Invention
The present invention relates in general to an apparatus for the measurement of the amount of airborne contamination. In particular, the present invention relates to an improved device for use in a medical clean room which will impact air upon a microbial growth medium, such that the growth medium may be cultured to determine the presence of airborne microbial particles within such clean room.
2. Description of the Related Art
It is a common practice to assemble, test and package various devices or articles within "clean rooms" to avoid or at least substantially reduce contamination of the articles with dust and/or biological contaminants, such as viable microbes. One particular application of such a clean room is the assembly of sterile medical devices or products. Currently, federal regulations allow a minimum acceptable number of viable airborne microbial particles per cubic foot of air within such a clean room.
Several devices are commercially available which will allow the determination of the amount of such airborne microbes within clean rooms. These devices generally consist of a housing which supports a motor to drive a shaft, from which extends a plurality of vanes. The housing includes an inlet port to allow air to enter and a peripheral wall surrounding the radially outer ends of the vanes such that air is drawn through the inlet and moved radially outward by the vanes to impact upon the peripheral wall. In use, an strip coated with agar growth medium is mounted on the interior of the peripheral wall such that the air displaced by the vanes will impact upon the agar strips and any airborne microbial material will be trapped thereon.
This operation is performed in the clean room and the agar strip thereafter removed from the device and cultured. This culture will reveal the amount of viable microbes within the volume of air impacted upon the agar strip, such that when the vanes are operated to displace a known amount of air the number of microbes per cubic foot may be calculated and thus determine if the clean room meets federal standards.
While this arrangement is serviceable, it is difficult to place and remove the agar strips about the interior of the peripheral wall due to the proximity of the vanes. Additionally, the agar strips are specially designed to be used within the specific device produced by that manufacturer, and must be purchased from the manufacturer of the device. Such strips are typically relatively expensive, thus increasing the cost of operating a clean room.